FMC - VNAV, waypoints and altitudes

This is my first serious venture into FMC programming. I have viewed the numerous YT video's, but I have not found an answer to this question. I understand that VNAV will get me to my FMC/MCP altitude settings but will the FMC automatically descend me to waypoint altitude settings or do I have to set altitude steps, commensurate with waypoints, on the MCP, to reach those descending altitudes?

The MCP needs to be reset from cruise alt to a lower altitude, or the aircraft won't descend.

On an Airbus, the descent even needs to be initiated manually by pushing the button on the MCP.

On a Boeing it goes automatic IIRC.

 

As I'm a lazy person, I mostly tend to reset the MCP directly to runway MDA (or somtimes the ILS entry altitude from the chart). Found out that's working OK, as the FMC will handle all the intermediate altitudes. So the intermediate steps don't need to be set. OTOH dunno if that's a good RW procedure.

 

Wim

Edited January 16, 2020 by f16jockey_2

The MCP needs to be reset from cruise alt to a lower altitude, or the aircraft won't descend.

On an Airbus, the descent even needs to be initiated manually by pushing the button on the MCP.

On a Boeing it goes automatic IIRC.

 

As I'm a lazy person, I mostly tend to reset the MCP directly to runway MDA (or somtimes the ILS entry altitude from the chart). Found out that's working OK, as the FMC will handle all the intermediate altitudes. So the intermediate steps don't need to be set. OTOH dunno if that's a good RW procedure.

 

Wim

 

Thanks. Interesting comment on Airbus vs Boeing. The AC I'm working with is the Quality Wings 757. After executing the flight plan in the FMC and seeing the waypoint altitudes under the Approach menu,it leads me to believe that these settings are simply for the pilot's memory to remind him to set the waypoints descending altitude on the MCP. Am I close on this assumption?

The AC I'm working with is the Quality Wings 757 (...) Am I close on this assumption?

I own the QW 757 package, but I don't fly it anymore. Never got the VNAV working correctly on that one. Maybe because it just isn't programmed?

I like the 757 btw, climbs like a rocket.

 

Wim

I own the QW 757 package, but I don't fly it anymore. Never got the VNAV working correctly on that one. Maybe because it just isn't programmed?

I like the 757 btw, climbs like a rocket.Wim

 

Surprisingly, I was successful in getting both the VNAV and LNAV to work on the first flight plan I entered. You are right about climbing like a rocket! I have been used to 1800' per minute with other AC in my hangar so I don't know if 2800' per minute is realistic. Most likely takeoff weight has something to do with that. One area that hasn't worked properly is the Autoland function but I think that is my fault in not selecting a high enough landing speed/flap configuration. I have been using the Autoland program by Stephan Liebe which has been working well on my other FSX AC, but not on the QW757. Well, not completely, but partially. When it activates, it sets a landing speed calculated on the weight of the AC but I have found that with my setup of the 757, the landing speed is too low. I have to set the landing speed about 10-15 knots higher than his program does. Even at flap 30, the AC drops below the glideslope. Has the QW757 Autoland worked for you?